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Organic Gardening and Pest Control

17/10/2019 @ 7:30 pm

Our October meeting was about organic gardening and pest control and we were very pleased to welcome Paul Hending as our speaker. A quick show of hands proved that most members were already trying to garden with the least impact on the environment, but we are always ready to learn more.

Gardeners today are much more likely to be organic and to avoid adding inorganic chemicals to the soil. We lighten up our heavy clay soils with well-rotted farmyard manure or barrowloads of spent mushroom compost. Of course, if you are offered the chance of a load of fresh manure, don’t pass it up, instead leave it for a year under cover to stop the nutrients being leached away by heavy rain. Another great soil improver is of course leaf mould and there is a vast amount of raw material around at this time of year! Let the leaves which land on borders remain for the worms to take down into the soil, enriching the soil for you and concentrate on raking up leaves on lawns and paths. Often, they can be swept under shrubs to rot down but all the rest can go into a container to make leaf mould for the coming years. If you have room, a leaf mould cage made from four bamboo canes or posts and chicken wire is ideal, but sacks with good aeration will do just as well. A good use for old compost bags so they aren’t single use plastic perhaps?

 

Paul ran through the steps to making good compost starting with the container, which needs to be ideally at least a cubic metre in size (any smaller and the process is more difficult). Two or three compost bins in a line are the best way forward – or more bays if you have the luxury of space. The compost can be turned from one bin into the next so that you can keep fresh material separate from the stuff that is cooking. This turning helps with aeration which is the key to keeping the micro-organisms alive. These break down the raw materials into beautiful sweet crumbly compost if you turn the heap at least once but more often if you have the energy. We were already aware of the need to keep a balance of brown twiggy material/broken up cardboard and green material, the soggiest of which tends to be grass clippings. Moisture is often the biggest problem with making perfect compost, too much and the mixture can become slimy (avoid this by covering it to keep the rain out); too little and it doesn’t seem to do anything (so water it). We were advised to avoid adding mouldy onions to the compost (as the blue mould can kill the bacteria in the heap) or too much citrus peel as it takes too long to decompose (unless you chop it up).

 

Paul then turned to pest control:

  • Crop Rotation – Aim for a 3 or 4 year crop rotation, avoiding growing the same crop in the same area year after year will help to prevent the build up of pests.
  • Vigilance – Look at beds, borders and containers regularly so that any pest incursion can be dealt with rapidly. This can be done by brushing/washing off aphids and picking off the offending caterpillar or lily beetle, though whether you squish them or feed them to the birds is up to you!
  • Biological response – Encourage the build up of natural predators such as lacewings, ladybirds and hover-flies in the garden. Lacewing and ladybird larvae can eat as many as 150 aphids per day. Birds will eat slugs, snails, grubs, wireworms, caterpillars and insects. Hedgehogs, frogs and toads will eat slugs and snails, beetles and insects. Build a beetle bank to encourage ground beetles which eat slugs, leatherjackets, cutworms and other caterpillars.
  • Biological controls – Plenty of these can now be purchased, such as Encarsia formosa, (a tiny parasitic wasp which will control greenhouse whitefly) and Phytoseiulus persimilis (a predatory mite which will control red spider mite). There are a variety of nematodes available to control slugs and vine weevils. In fact, there seems to be a biological control to deal with most garden pests. The RHS web site has a comprehensive list.
  • Physical Barriers – Netting with enviromesh seems to be the best way forward to keep white butterflies from laying eggs on your brassicas. A mesh barrier around the carrot plot will deter the carrot root fly too.
  • Traps – Earwigs can devastate seedlings and soft fruit or sweetcorn silks. Try filling a few plastic flowerpots with straw and balancing them upside down on sticks to attract the pests. The earwigs crawl up the poles and take shelter in the pots at night and you can empty them and dispose of the pests in the morning. Sticky bands placed on the trunks of trees can stop pests from reaching the fruit.

 

We also discussed getting sowing times right to avoid pests such as black bean aphid, and the use of so-called organic pesticides and slug pellets. Not everyone was happy with the idea of killing garden pests, particularly the white butterflies, especially as the numbers of butterflies generally are declining. It made for a lively discussion.

 

Sadly, because a general election has been sprung on us, we are having to cancel our meeting in December and with it our eagerly anticipated seasonal social and quiz. I wish all gardening readers a very Happy Christmas and a productive New Year.

 

 

 

Pauline Bartlett    

Details

Date:
17/10/2019
Time:
7:30 pm

Venue

Otterford Parish Hall, Bishopswood.
Bishopswood Somerset TA20 3RS + Google Map